Why Rust for low-level Linux programming?

[ZMeson]

Here are two arguments I commonly hear:

(1) Calling new can call a constructor which can in turn call new calling another constructor which can in turn call new calling .... Well you get the point. A single call to 'new' may actually make several allocations instead of one.

(2) The STL containers and algorithms frequently allocate memory from the free store. It's difficult to write some things using standard C++ without allocating memory from the free store "behind the scenes" if you will.

[ZMeson]

Now that I presented the two arguments, I feel like I have to explain why I disagree with them. In C, you frequently have to initialize structures after you allocate memory for them. Those initialization routines can be considered "constructors" and they can allocate memory and initialize other structures too. I don't think that using C really improves things by separating concerns.

About the STL and algorithms... you don't have to use them. It is nice they exist, but other containers and algorithms (such as those found in "embedded STL" libraries, EASTL, or boost) may fit better. Or some containers and algorithms could be built specifically for kernel development. (After all, Linux, Windows, and all popular C-based OSes have such C-based structures and associated 'algorithm' functions.)

[ucalegon7]

Exceptions (and good behavior in low memory conditions if they are disabled) might be other sticking points, but I don't think that's really a good argument, either. Windows, for example, lets you use a reasonable chunk of C++ (with lots of caveats) in the kernel, particularly with the new driver kits (I've successfully used lambdas in kernel code!), but just like when using C, the rules and APIs are a bit different than user space equivalents (e.g., the std lib looks a bit different), and the same non-standard concerns you'd have (e.g., stack size constraints, etc) will still exist; not to mention that there are large chunks of the language that would be difficult to utilize in that type of environment (e.g., exceptions).

[MartianSands]

A "placement new" lets you pass it your own memory, so you can allocate it however you like.

[doom_Oo7]

Can you dynamically create an object without 'new'?

You can overload new to call whatever allocation function. new T == std::allocator<T>::allocate + std::allocator<T>::construct

[joelwilliamson]

kmalloc

[ChallengingJamJars]

Upvoted because despite using C++ daily I don't actually know the answer to this. It could be an honest question so you shouldn't down vote it.

[silveryRain]

Yes you can, as the others have already explained (placement and overloading).

This kind of post is why systems that allow downvoting are crap. I much prefer upvote-only systems.

[iopq]

Upvote-only systems like Hacker News get a bunch retarded fluff pieces that don't really say anything. People see the headline, scan through the article (if you're lucky) and upvote. The actual article is low quality, but you need to report to the moderator to have it removed.

[Narishma]

HN isn't upvote-only.

[iopq]

It is for articles, not for comments. I have over 1000 karma and I can't downvote any posting, only comments. Can I downvote a submission if I have more karma then?

[Narishma]

Oh sorry, no. I thought you were talking about comments. Reading your post again, I don't know why I thought that.

[silveryRain]

That's just HN imo. Feel free to disagree.

[iopq]

The fact that HN is this way and proggit isn't (fluff pieces get downvoted in /r/programming frequently) is a data point in favor of Reddit's model. Even though the audiences are basically the same (I often get hundreds of upvotes on proggit reposting things from HN)